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Date:      Fri, 9 Sep 2005 14:48:08 -0700
From:      Brooks Davis <brooks@one-eyed-alien.net>
To:        Jung-uk Kim <jkim@freebsd.org>
Cc:        freebsd-arch@freebsd.org
Subject:   Re: time_second vs. time_uptime
Message-ID:  <20050909214808.GA6021@odin.ac.hmc.edu>
In-Reply-To: <200509091744.26505.jkim@FreeBSD.org>
References:  <200509091744.26505.jkim@FreeBSD.org>

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On Fri, Sep 09, 2005 at 05:44:24PM -0400, Jung-uk Kim wrote:
> If I read the source correctly, time_second can go backwards or=20
> forwards when there is a leap second but time_uptime cannot.  Am I=20
> right?  If my assumption is right, it seems we have some misuses in=20
> kernel, e. g., sched_sync() in sys/kern/vfs_subr.c.  It may not be=20
> critical but it worries me a little because a leap second is=20
> scheduled to occur at the end of this year. ;-)

Yes, uptime increases monotonically, but leap seconds and adjustments such
as those made by ntpdate will make simple time values jump around.  This
bit me when I first did the interface epochs since absolute times
are not necessarily unique.

-- Brooks

--=20
Any statement of the form "X is the one, true Y" is FALSE.
PGP fingerprint 655D 519C 26A7 82E7 2529  9BF0 5D8E 8BE9 F238 1AD4

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